Dorrans (left) is the second West Brom player, after Peter Odemwingie, to score and provide two assists in a Premier League game

The game's first serious chance fell to the visitors, Michael Kightly firing over from 20 yards after the Baggies defence had failed to deal with Ross Wallace's corner.

It was one-way traffic after that.

Brunt had already gone close when defender Dawson towered above the Clarets defence to head home from a corner after half an hour.

Tom Heaton produced a fine fingertip save to keep out a vicious 35-yard attempt by Dorrans in the 43rd minute.

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Dyche critical of 'poor' Burnley

But there was nothing the Burnley keeper could do as Berahino made it 2-0 after Morrison's corner had been flicked on by Dorrans on the stroke of half-time.

Dyche made a double change at the interval as Ashley Barnes and on-loan Chelsea midfielder Nathaniel Chalobah replaced former Baggies defender Steven Reid and Ross Wallace. But it failed to stem the flow of West Brom attacks.

Berahino made it 3-0 in the 57th minute with a cool shot across Heaton following a delightful threaded pass by Dorrans.

Foster was called into action to tip Jutkiewicz's header over the bar.

But Dorrans capped a fine performance with a first-time finish from Cristian Gamboa's 90th-minute cross to round off Irvine's most satisfying day since taking charge of Albion in June.

"Saido Berahino can be very good. He's a terrific lad and very, very talented. I spoke to him at half-time and said to be patient and continue making runs. He got his reward for continuing to do that. He's a model professional and has fantastic potential."

Burnley manager Sean Dyche: "We never got started and never got to grips with the game at all. It's a real low day for us performance-wise.

"There is a reality to it, we've seen results like this in the Premier League and it's happened to us and it's important we grow and learn from it very very quickly."

West Brom defender Craig Dawson started his career in non-League at Radcliffe Borough

West Brom striker Saido Berahino (second left) has five league and cup goals in eight games this season

The previous four times West Brom scored three goals or more in a Premier League game, they failed to win

Burnley have failed to keep a clean sheet in any of their last 19 games against West Brom in all competitions